Issue Description:

swift-format crashes due to a segmentation fault when using the --parallel flag. The cause of the crash appears to be different depending on build configuration.

When using debug configuration, the segfault happens if the lineBreakBeforeEachArgument option is enabled. Disabling the line break option avoids the error.

When using release configuration, the segfault happens when using the --configuration option, even if the provided configuration file contains the default options from the dump-configuration command. Omitting the --configuration option avoids the error.

I use Mint to manage swift-format, which means I typically have a release build. I have a custom configuration file, meaning I am unable to use parallel mode. I could use a debug build, but I enable the lineBreakBeforeEachArgument option, so parallel mode still doesn't work for me.